Stockholders' Equity And Stock-Based Compensation (Narrative) (Details) - USD ($)			3 Months Ended				6 Months Ended	9 Months Ended
	Jan. 01, 2019	Dec. 06, 2018	Sep. 30, 2019	Sep. 30, 2018	Sep. 30, 2017	Jun. 30, 2017	Jun. 30, 2018	Sep. 30, 2019	Sep. 30, 2018	Dec. 31, 2018	Oct. 25, 2018	Nov. 30, 2017	Dec. 31, 2016	Dec. 31, 2014
Stockholders' Equity [Line Items]
Common stock, par value			$ 0.001					$ 0.001		$ 0.001
Proceeds from issuance of common stock under employee stock purchase plan								$ 423,000	$ 327,000
Common stock, shares issued			20,788,000					20,788,000		20,593,000
Total stock-based compensation expense			$ 2,679,000	$ 3,393,000				$ 7,739,000	9,988,000
Cash received from option exercises								$ 272,000	423,000
2017 Employee Stock Purchase Plan [Member]
Stockholders' Equity [Line Items]
Common stock, shares issued			38,279					38,279
Shares authorized			250,000					250,000
Increase in shares available for issuance threshold of common stock outstanding, number of shares								450,000
Increase in shares available for issuance threshold of common stock outstanding, percent outstanding								1.50%
Shares available for grant			440,195					440,195
2017 Inducement Equity Incentive Plan [Member]
Stockholders' Equity [Line Items]
Term period								10 years
Shares authorized												1,000,000
Shares available for grant			190,875					190,875
2017 Plan [Member]
Stockholders' Equity [Line Items]
Term period								10 years
Shares authorized			1,500,000					1,500,000
Additional common stock reserved for issuance	823,716
Increase in shares available for issuance threshold of common stock outstanding, number of shares								1,200,000
Increase in shares available for issuance threshold of common stock outstanding, percent outstanding								4.00%
Shares available for grant			1,090,058					1,090,058
First Vesting Portion [Member] | 2017 Inducement Equity Incentive Plan [Member]
Stockholders' Equity [Line Items]
Vesting percentage								25.00%
Sales, general and administrative [Member]
Stockholders' Equity [Line Items]
Total stock-based compensation expense			$ 1,735,000	2,483,000				$ 4,881,000	7,533,000
Research and development [Member]
Stockholders' Equity [Line Items]
Total stock-based compensation expense			$ 944,000	910,000				$ 2,858,000	2,455,000
Options [Member]
Stockholders' Equity [Line Items]
Options granted								917,182
Warrants exercised								98,928
Exercise price			$ 16.18					$ 16.18
Restricted Stock Units [Member]
Stockholders' Equity [Line Items]
Units granted during period						160,974		40,582
Reduction to APIC from shares withheld for tax						$ 100,000		$ 400,000
Total stock-based compensation expense			$ 0	0				$ 0	2,100,000
Performance Shares [Member]
Stockholders' Equity [Line Items]
Options granted							31,875
Private Placement [Member]
Stockholders' Equity [Line Items]
Common stock, par value														$ 0.001
Certain Employees [Member] | Restricted Stock Units [Member]
Stockholders' Equity [Line Items]
Units granted during period					68,800			17,456
Reduction to APIC from shares withheld for tax								$ 200,000
Total stock-based compensation expense			$ 100,000	$ 100,000				$ 300,000	$ 300,000
Certain Employees [Member] | Restricted Stock Units [Member] | First Vesting Portion [Member]
Stockholders' Equity [Line Items]
Vesting percentage					50.00%
Certain Employees [Member] | Restricted Stock Units [Member] | Second Vesting Portion [Member]
Stockholders' Equity [Line Items]
Vesting percentage					50.00%
Certain Employees [Member] | Restricted Stock Units [Member] | Change In Control [Member]
Stockholders' Equity [Line Items]
Vesting percentage					100.00%
Common Stock
Stockholders' Equity [Line Items]
Warrants exercised				62,000				99,000	117,000
Common Stock | Rights Offering [Member]
Stockholders' Equity [Line Items]
Net proceeds		$ 44,800,000
Right entitlement to holder		3,581,148									0.19860755
Exercise price of warrants/rights											$ 12.57
Common Stock | Warrants [Member]
Stockholders' Equity [Line Items]
Warrants exercised				24,000					24,000
Common Stock | Chairman, Robert W. Duggan [Member] | Rights Offering [Member]
Stockholders' Equity [Line Items]
Ownership percentage		35.00%
Shares purchased		3,146,226
Investment		$ 39,500,000
MDB Capital Group, LLC [Member] | Initial Public Offering [Member]
Stockholders' Equity [Line Items]
Price per share													$ 5.00
Warrants/rights outstanding			121,609					121,609
Exercisable period of warrants or rights								5 years
Number of common shares called by issuance of warrants													574,985
MDB Capital Group, LLC [Member] | Private Placement [Member]
Stockholders' Equity [Line Items]
Price per share														$ 2.67
Warrants/rights outstanding			91,876					91,876
Exercisable period of warrants or rights								7 years
Number of common shares called by issuance of warrants														299,625